Elecraft KX3 Owner's Manual - Manual (Page 46)

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§ Received signal level too low: (1) check headphone and speaker plugs and cables; (2) make sure that
MENU:RX EQ has not been set for large cuts; (3) verify that MENU:REF CAL is properly adjusted; (4)
make sure RF gain is set to maximum; (5) preamp set to 10 dB rather than 20 dB (MENU:PREAMP).
§ Spurious signals (“birdies”): All receivers exhibit some birdies. Most will be inaudible with an antenna
connected. In the KX3, there may be significant birdies or harmonics of birdies at the following frequencies
due to internal signal sources: 16000 and 18432 +/- 5 kHz (MCU and DSP clock frequencies), 300-900 kHz
(DC-DC converter oscillators, CMOS RF switches). In the unlikely event that a birdie interferes with
operation, try CW reverse, manual notch, or (in voice modes) auto-notch.
§ Opposite-sideband images heard: Opposite-sideband suppression is 50-60 dB. If images appear too high
in amplitude, carefully redo the Receive Sideband calibration procedure (pg. 32). If sideband image
rejection is poor only for FL2 and/or FL3, but not FL1, the KXFL3 roofing filter module may be at fault.
§ VFO tuning noise heard: Set VFO NR (VFO noise reduction) to O N on the affected band, and/or set
RX SHFT to 8.0. Even with these settings there may be very weak tuning noise heard, especially when no
antenna is connected. Dual RX and roofing filters are disabled on any band where RX SHFT is set to 8.0.
§ Mobile installation noise: If the 12-V DC accessory jack in a vehicle causes interference to the KX3’s
receiver, try setting RX SHFT to 8.0 on the affected band(s).
§ Low-level signals are heard that don’t change as the VFO is rotated: In a zero-I.F. receiver, it’s possible
for extremely strong signals to create audible artifacts, due to AM detection at the mixer, that are not
affected by tuning the VFO. If this occurs, first try turning off the preamp (and/or turning on the attenuator).
Another alternative is to set the RX SHFT menu entry to
8.0 (kHz) on the affected band(s), although with
this setting, dual watch cannot be used. If the source of such signals is a nearby transmitter (such as at Field
Day), you may be able to reorient or move one of the antennas, or use an external band-pass filter.
§ KX3 VFO signal is heard in a nearby receiver: If a nearby receiver is picking up the KX3’s VFO signal,
turn on the isolation amp (RX ISO menu entry). Note: This increases current drain by about 15 mA if the
isolation amp was not already being used as a 10-dB preamp. Turn RX ISO off when not needed.
§ Internal speaker distortion at high volume: The KX3’s small internal speaker is not intended for use in
high-noise environments, such as in a vehicle or outdoors in high winds. If audible artifacts occur at higher
volume levels, switch to headphones or an external speaker. (Stereo also allows the use of audio effects.) If
you hear distortion products even at low levels, verify that the speaker plug is inserted exactly as shown in
Fig. 17 of the KX3 assembly manual. Also try loading new firmware (rev 1.41 or later improves audio).
§ AM broadcast signals in the 300-700 kHz range appear to be off-frequency: Broadcast signals that
appear not to tune in at even multiples of 1 kHz may be images of signals higher up in the band. You can
eliminate most images by installing the KXAT3 ATU option, which includes broadcast band filtering.
Parameter Initialization (EEINIT)
It is possible, though rare, for EEPROM parameters to become altered in such a way as to prevent the firmware
from running correctly. If you suspect this, you can reinitialize parameters to defaults, then restore a previously-
saved configuration (or re-do configuration steps manually; no test equipment is required). To initialize:
§ IMPORTANT: Run the KX3 Utility program and use the Save Configuration function to save your
present firmware configuration. (Otherwise, you’ll need to re-do calibration steps after EEINIT.)
§ Turn the KX3 off (using the KX3’s on/off switch combination, not your power supply).
§ While holding in the P B T I / I I knob with your right hand (which is also labeled NORM below the knob),
turn power on with your left hand by holding B A N D - and A T U T U N E together for about 2 seconds, then
release. Release the P B T I / I I knob after another few more seconds. You should see E E IN IT on the LCD.
§ When E E IN IT completes, you may see E R R nnn due to initialization. Tap D I S P to clear messages.
§ Restore all parameters using the Restore Configuration function of the KX3 Utility program. Then turn
power off and on again. See if the original problem has been resolved. If not, contact Elecraft.